Practical and efficient generation of electrical energy has been sought since the discovery of electricity. Fuel cells are becoming a viable alternative to hydroelectric, fossil fuel and nuclear energy. Fuel cells efficiently convert a fuel's chemical energy directly to electrical energy. They chemically combine a fuel and oxidant without burning, thereby eliminating many inefficiencies and most pollution of traditional combustion power systems.
There are five main known types of fuel cells: alkaline fuel cells (AFCs), proton exchange membrane fuel cells (PEMs or PEMFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs).
A fuel cell operates in principle much like a battery. In general, a fuel cell consists of two electrodes (an anode and a cathode) sandwiched around an electrolyte. For example, for a PEM fuel cell, hydrogen and oxygen are passed over the anode and cathode electrodes respectively in a manner that generates a voltage between the electrodes, creating electricity and heat, and producing water as the primary byproduct. The hydrogen fuel is supplied to the anode of the fuel cell. Oxygen enters the fuel cell at the cathode. The oxygen can be supplied in purified form or can come directly from atmospheric air.
All of the known fuel cell configurations discussed above have a common need for oxygen as an integral ingredient for performing the cell's chemical process. For most commercial applications it is desirable for such oxygen to be supplied directly from the atmospheric air. However, it is accepted that in today's world, all atmospheric air has some degree of contaminants present in it, both particulate contaminants such as loose debris, insects, tree blossoms, dust, tree pollen, smog, and smoke particulates, and chemical contaminants such as volatile organic compounds (such as aromatic hydrocarbons, methane, butane, propane and other hydrocarbons) as well as ammonia, oxides of nitrogen, ozone, smog, oxides of sulfur, carbon monoxide, hydrogen sulfide, etc.
Since efficient fuel cell operation depends on a delicately balanced chemical reaction, contaminants in the air used by the cell can have a significant adverse effect on the cell's operation and, depending on their nature, can even cause the fuel cell to discontinue operation. It is important therefore, that the fuel cell system include a filtration system that is designed to eliminate harmful contaminants and one that enables the fuel cell to be used in a wide range of use environments.
To obtain the amount of oxygen necessary for a fuel cell to produce the desired energy output, it has been found desirable to pass the oxygen-containing air through air movement equipment such as a compressor or fan located within the airflow stream supplied to the fuel cell or other equipment. Unfortunately, typical compressors produce significant undesirable and annoying noise levels. It is desirable to reduce the noise produced by and/or transmitted through the compressor and back into the environment. The present invention addresses the above-identified needs and desires for an efficient and quiet system for use in a wide variety of applications, including fuel cell systems.
What is desired, therefore, is a power generator, such as a fuel cell, that functions within environments having a wide range of contaminants.